1. Field of Use
This invention pertains to the analysis of spectra to determine the presence or absence of particular constituents in media undergoing evaluation. More particularly, this invention relates to the fast, real-time analysis of spectra.
2. Description of the Related Art
It is the nature of testing, particularly testing in disciplines where even the slightest error is unacceptable, to employ a variety of tests a number of times until the chance of error has been virtually eliminated. The costs of testing and retesting until all possible tests are exhausted is great and, unfortunately, is often precipitated by none other than the desire to avoid liability if the test results are wrong. At the same time, it is commonly necessary, and indeed crucial, to determine the constituents, chemical or other, of particular media. "Constituents" may include molecular, elemental, structural, crystalline, or physical characteristics, and which may be represented by an XY plot. Spectrometers or a variety of devices such as mass spectrometers, NMR and electron spin resonance device and others, are means commonly employed to determine the chemical and physical characteristics of media.
The output of a spectrometer is a "spectral signature" which is a characteristic complex curve or spectrum having peaks and valleys of various amplitudes, and which, in the absence of noise, are identifiable by the operator as being associated with a particular composition. A "spectrum" may be an XY plot where the X axis could be intensity, for example, transmission, absorbance or relative counts, polarization, degrees of temperature or angle, energy or force. The Y axis could be wavelength units, wavenumber units, mass, time, force, energy, magnetic movement, or gauge. When a number of constituents having similar characteristics are to be determined, it becomes more difficult to identify and distinguish between some or all of them. Furthermore, that task can be made almost impossible in the presence of significant noise. A variety of commonly used methods, including Fourier transform analysis, on occasion may be used to improve the signal-to-noise ratio of such a signal but all current methods make the testing process more expensive because they require the skilled use of additional equipment and are relatively slow.
Furthermore, the usual course in the state of the art is to run a full battery of post spectroscopic tests for all conceivable constituents so that none are missed. These tests confirm not only the presence or absence of a particular constituent but its exact quantity and therefore are costly and time consuming. Such comprehensive testing is cost effective where the constituent tested for is in fact found to be present but is wasteful where the constituent is absent altogether.